(CNN) - Few might realize it, but Tuesday's primary elections might have quietly sealed the racial and ethnic makeup of the U.S. Senate for a couple of more years.

On Tuesday, C. Anthony Muse, thought to be the strongest black candidate for U.S. Senate this year, lost his Democratic primary race in Maryland, coming in a distant second to Sen. Ben Cardin, the incumbent. CNN found only one other African-American on a Senate ballot, a Florida candidate who isn't getting much attention among a wide field of contenders.